Speed-changing spur-gear train



(No Model.)

J. THOMSON. SPEED CHANGING SPUR GEAR TRAIN.

N0. 535,643. Patented Mar. 12,1895.

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-INVENTOR ATTORNEYS UNITED STATES PATENT OFFIGE.

JOHN THOMSON, OF BROOKLYN, NEW YORK.

SPEED-CHANGING SPUR-GEAR TRAlN-.

SPECIFICATION forming part of Letters Patent No. 535,643, dated March12, 18995. Application filed August 24,1894. Serial No. 52l,228. (Nomodel-l To all whom it may concern:

Be it known that 1, JOHN THOMSON, a citizen of the United States,residing at Brooklyn, in the county of Kings and State of New York, haveinvented certain new and useful Improvements in Speed-Changing Spur-Geargrains, of which the following is a specifica- My invention relates tospeed -changing spur gear trains, and it has for its object to provide aconstruction which shall avoid the objections due to the side thrustsordinarily inherent to such trains, to provide a structure in which thestrains shall be balanced as far as practicable, to provide a device inwhich the errors due to the faulty development of the contour of theteeth are reduced to a minimum, and further to provide a gear trainwhich shall be simple, cheap and effective in mode of operation, andshall avoid the objections to such trains as heretofore made, and tothese ends, my invention consists in the various features ofconstruction and arrangement of parts substantially as hereinafter moreparticularly pointed out.

In the accompanying drawings, 1 have shown one embodiment of myinvention, sufficient to enable those skilled in the art to make usethereof, and while the form shown is the preferred form, itis to beunderstood that my invention is not limited to the construction andarrangement of parts therein set forth, but that the same principles ofinvention may be applied in various modified forms, producingsubstantially the same results. Furthermore,lhave shown my invention ina form adapted for use in water meters, and the invention is especiallyuseful in this connection, but it is to be understood that it can beused in many and various places where the object is to produce theminimum of frictional resistance, the maximum of durability, and thelowest cost of manufacture.

In the drawings: Figure 1, is an elevation of the train shown as appliedto the casing of awater meter, which latter is indicated in the dottedline A. The front pillar 5, is omitted in this figure for clearness.Fig. 2, is a top plan view of the train, the upper plate 3, beingremoved. Figs. 3 and 4:, are diagrams, illustrating the principle andmode of operation of the parts.

One of the principal features of 'my invention consists in providingthree. series of superimposed gears and pinions, all disposed inapproximately the same plane, the central series, comprising the primarydriving, and the final driven member of the train, and the two outerseries of gears and pinions which mesh with the central series in themanner hereinafter more particularly set forth.

I have shown my device as employed for speed reduction in which thedriving pinion is the high speed pinion, and the driven pinion is thelow speed pinion,but it is to be understood, of course, that the partsmay be reversed, and the low speed pinion may be the driving pinion, andthe same advantageous results obtained.

It will be observed that both the driving member and the driven memberof the gear train are contained in the central series of gears. 'lhus,inthe arrangement shown, the primary driving pinion 6,is fixed to aspindle 7, mounted on the lower plate 4, and in the present instancethis spindle has an arm or other means 8, by which it is driven, as bythe spindle Oof the disk meter action D. The said pinion 6, meshes rightand left with driven gears 9 and 10, having pinions 11 and 12,respeetively fixed thereto. These gears and pinions are free to revolve,being mounted upon the uprightaxles or spindles 13, 14, confined in theupper and lower plates 3 and 4:. The next transmission is fromthedriving pinions 11 and 12 to the single lower central driven gear wheel15, to which gear is fixed a pinion 16, and both the gear and pinion arefree to rotate on the lower extension 17 of the spindle 18 of the drivengear, the collar or head 19 supporting the gear and pinion in properposition on the spindle. Of course, instead of mounting this gearandpinion on an extension of the driven spindle, it may be mounted on anextension of the driving spindle, or even independently mounted, themain feature being that it is supported between the driven and drivinggears in a line with their axes. The next transmission is from thesingle central driving pinion 16, right and left to the two upper drivengear wheels 20, 21, to which wheels are respectively fixed the drivingpinions 22 and 23, but both of these gear wheels and pinions are freelymounted upon the upright axles 13, 14, and in the present instance theirweight is borne by'the collars 24, 25, fast to the axles. The finaltransmission is from the two driving pinions 22, 23, acting right andleft upon the single upper center driven gear 26, which is fixed to thedriven spindle 18 in the present instance, and thus becomes the finaldriven member of the train, it being shown as passing through thestufiing-box of the water meter casing. It is evident that this samearrangement may be extended to a greater or less extent by adding morepinions and gears, arranged in substantially the manner set forth, sothat any amount of reduction or increase of speed may be attained.

From this arrangement of the parts, it will be seen that no side thrustsare borne by either the spindles or the bearings of the central seriesof the train, while the side thrusts transmitted therefrom right andleft to the two outer series are not only materially reduced inintensity, but are borne and resisted by twice the projected area thatwould be afforded by a single series.

Among the practical advantages arising from this construction andarrangement are that whatever Wear may take place both upon the highspeed spindle, as 7, and also in its bearing in the plate, it will beuniformly distributed, that is, it will be cylindrical, incontradistinction to the oblong wear or bearing produced by simplesingle spur trains, which cause the wear to take place chiefly in thedirection of the side thrusts. So also the same advantages apply withequal, if not greater, force to the final driven member, as the spindle18, which is required to be revolved against the greater frictionalresistance of the stuffing-box, for instance, besides having to drivethe exterior gearing of a register in the case of a water meter or otherapparatus in other cases, and is shown as provided with the gear 27 forthis purpose. Furthermore, by thus compounding the train and therebybalancing the strains upon the central series of gears, as will be seenmore particularly by reference to the diagrams, Figs. 3 and 4, anddoubling the working contacts, it becomes feasible to considerablyreduce the diameters of the axles supporting the gears and pinions, andto use teeth of finer pitch and less breadth of face than would bepractical with'a single train system. Furthermore, it is desirable in aconstruction like that described that the radial 10- cation oftheleavesof each pinion with respect to the teeth of the gear to which it isfixedand with which it rotates shall be exactly similar to that of everyother gear and pinion. In other words, if a line drawn through theleaves of one pinion should pass through spaces of its gear, while theleaves of another pinion should point toward the teeth of its gear, thenthe driving stresses would not be in balance, and the teeth of thetrain, if accurately cut and located, would jam sidewise. Theconstruction and disposal here contemplated are clearly indicated inFig. 2, showing what may be said to be the initial setting up of thetrain, a leaf in each pinion and two spaces in the gear all lying in thesame right line, B. In this wise, the stresses and resistances, as indicated in the diagram, Figs. 3 and 4, will'be 'fullyrealized in practice.

Having thus pointed out the general principles of my invention and theresults and advantages of the construction, as well as the preferredform of embodying it, what I claim is- 1. A spur gear train, comprisinga central series of superimposed gears and pinions containing theprimary driving member and the final driven member of the train, and twoouter series of superimposed gears and pinions meshing with the centralseries, the axes of the several series being disposed in ap' proximatelythe same plane, substantially as described.

2. A spur gear train, comprising a central series of gears and pinions,and two outer series of gears and pinions disposed to the right and leftand mes-hing with the central series, and fixed spindle on which thesaid outer series are mounted, substantially as described.

3. The combination with the upper and lower gear plates, of the axlessupported in said plates collars fixed to said axles the two outerseries of gears and pinions mounted thereon, and separated by saidcollars, a central series of gears and pinions the driven spindle ofwhich is mounted in one plate,and the driving spindle of which ismounted in the other plate, substantially as described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

' JOHN THOMSON.

Witnesses:

ROBERT S. GHAPPELL, MEYER KRASUER.

